An organic polymer containing a reactive silicon group in the molecule has a property such that even at room temperature the organic polymer is cured into a rubbery state by a reaction with moisture in the air. Among the organic polymers having a reactive silicon group in the molecule, organic polymers in which the main chain skeleton is a polyoxyalkylene polymer are disclosed in (Patent Document 1) and the like. Those polyoxyalkylene polymers have already been industrially produced, and are widely used in applications to sealants, adhesives and the like. Representative examples of those organic polymers usually have reactive silicon groups having two hydrolyzable groups bonded to one silicon atom for maintaining elongation and flexibility.
Curable compositions comprising the above described organic polymers are cured by using silanol condensation catalysts, and usually organotin catalysts such as dibutyltin bisacetylacetonate are widely used. However, in recent years, toxicity of organotin compounds is pointed out, and alternative non-tin curing catalysts are desired.
Dealcoholization type silicone compositions using titanium catalysts as a non-organotin catalyst are disclosed in (Patent Document 2), (Patent Document 3) and the like. Those dealcoholization type silicone compositions have already been industrially produced, and are widely used in a variety of applications.
On the other hand, curable compositions prepared by combination use of organic polymers having reactive silicon groups and curing catalysts such as a titanium catalyst, an aluminum catalyst or a zirconium catalyst are disclosed in (Patent Document 4), (Patent Document 5), (Patent Document 6), (Patent Document 7) and the like.    Patent Document 1: JP-52-73998A    Patent Document 2: JP-39-27643B (U.S. Pat. No. 3,175,993)    Patent Document 3: U.S. Pat. No. 3,334,067    Patent Document 4: JP-2002-249672A    Patent Document 5: JP-58-17154A (JP-3-57943B)    Patent Document 6: JP-62-146959A (JP-5-45635B)    Patent Document 7: JP-2004-51809A